Polymer photo-detectors are sought after for the purpose of photo-detection and measurement of photoconductivity and pyroelectric characteristics due to their low-cost and simple fabrication capability. Traditional silicon photo-detectors absorb only below 1.1 μm, which means that they can only be operated within visible waveband and Near Infrared, hence having limited applicability. Further, the aging of device and radiation effects further lower its Quantum efficiency.
The existing prior art explains the method for manufacturing photo-responsive devices as well as broadband photo-detectors. They all include devices comprising a number of layers fabricated onto one another. These multiple depositions are provided for enhancing and blocking the charge carriers for photoconduction. The multiple layers make the device bulky as well as expensive.
In U.S. Pat. No. 6,670,213 B2, titled “Method of Preparing Photoresponsive Devices, and Devices Made Thereby,” a method of preparing a photoresponsive device is explained which includes fabricating a first electrode on a substrate, forming a layer of an organic material including a blend of at least two semiconducting polymers having different electrode affinities and/or different ionization potentials over the first electrode, and providing a second electrode over the layer of organic material. The method requires at least one of the electrodes as transparent or semi-transparent, to form a photo responsive device, and thermally anneals the photo responsive device. It requires two semiconducting polymers for operation in broadband.
US Patent Publication No. 2013/0248822 A1, titled “Broadband Polymer Photodetectors Using Zinc Oxide Nanowire as an Electron-Transporting Layer,” describes a semiconductor polymer thin-film based photodetector with enhanced spectrum and fast temporal response having inverted type structure. It includes an indium-tin-oxide (ITO) as cathode and anode that is separated with a sandwiched photoactive layer of PDDTT and PCBM formed with a composite of conjugated polymers. Also, a cathode buffer layer formed as a matrix of Zinc Oxide (ZnO) nanowires is disposed upon the ITO cathode, while a MoO3 anode buffer layer is disposed between a high work-function metal anode and the active layer. The extraction of charge carriers and blocking of holes are done by ZnO nanowires. There are multiple depositions for enhancing and blocking the charge carriers for photoconduction. The multiple layers decrease the cost effectiveness of the photodetector.
In view of the foregoing, there is a need for a simple photo-detector with low-cost photoactive polymer with a simplified single layer deposition and easy fabrication for multi-wave band response. In addition, there is a need for a miniaturized photo-detector with low thermal mass and adaptability for any kind of detection system.